1. Field of the Invention
This invention relates to an electro-optical imaging apparatus and more particularly to an electro-optical imaging system, having at least one array of N image viewing or picture elements, which automatically detects any picture element failures.
2. Description of the Prior Art
In the electronic art of electro-optical imaging, raster scanners employing at least one array comprised of a plurality of image viewing elements are being increasingly used. Such multielement arrays may be comprised of, for example, a charge coupled device (CCD) array or a photodiode array.
Many different types of apparatuses and systems have been proposed for controlling the operation of such imaging equipment. Prior art raster scanners employing multielement arrays have been proposed for controlling the integration time of the arrays (see U.S. Pat. Nos. 3,944,816 and 4,174,528), controlling the gain of the arrays (see U.S. Pat. Nos. 3,717,077 and 4,287,536), correcting for variations in the outputs of individual elements (see U.S. Pat Nos. 4,228,468 and 4,298,887) and removing the noise caused by defects in the semiconductor crystal of the CCD device (see U.S. Pat. Nos. 4,167,755 and 4,189,751).
All of the above-described apparatuses and systems are basically directed to controlling various operational aspects of electro-optical imagers employing at least one multielement array.
Applicant's above-described U.S. Patent application Ser. No. 450,582, for "Automatic, Self Diagnosing, Electro-Optical Imaging System" uses signals, including the center pixel of at least one array in an electro-optical imaging system to perform self-diagnostic tests on itself. This self-diagnosing system utilizes a center pixel derived from an imaging sensor to determine whether or not an associated video processor is defective.
None of the above-described apparatuses or systems teaches or suggests any means for testing each of the elements in a multielement array to detect and identify picture element (pixel) failures.
The background art known to the applicant at the time of the filing of this application is as follows:
U.S. Pat. No. 3,717,077, Exposure Control Apparatus, by Harvey;
U.S. Pat. No. 3,944,816, Charge Transfer Apparatus Having Light Sensitivity Control Means, by Harada;
U.S. Pat. No. 4,167,755, Solid State Television Camera, by Nagumo;
U.S. Pat. No. 4,174,528, Exposure Control For Document Scanner Arrays, by White;
U.S. Pat. No. 4,189,751, Solid State Television Camera With Defect Compensation To Reduce Noise, by Nagumo;
U.S. Pat. No. 4,228,468, Output Correcting System For Facsimile, by Nagano et al.;
U.S. Pat. No. 4,287,536, Gain Control For Scanning Arrays, by Wiggins; and
U.S. Pat. No. 4,298,887, Non-Uniformity Correction In A Multielement Detector Array, by Rode.